The present invention relates to a method to increase blood levels of one or more parasiticides by administering those one or parasiticides to the nasal pharynx of animals, including humans. In certain embodiments, Applicants"" invention relates to a method to increase blood levels of one or more macrocyclic lactone parasiticides by administering those one or macrocyclic lactone parasiticides to the nasal pharynx of animals, including humans. In certain embodiments, Applicants"" invention relates to a method to increase blood levels of ivermectin by administering ivermectin to the nasal pharynx of animals, including humans.
The avermectin family, of which ivermectin is a member, is a series of very potent antiparasitic agents which are useful against a broad spectrum of endoparasites and ectoparasites in mammals. Ivermectin is disclosed in U.S. Pat. No. 4,199,569, issued Apr. 22, 1980 to Chabala and Fisher. Ivermectin is a mixture, in the ratio of approximately 80:20 of 22,23-dihydro C-076 B1a and B1b.
Ivermectin is a member of a family of compounds identified as avermectins. The basic avermectin compounds are isolated from the fermentation broth of the microorganism Streptomyces avermitilis. Such compounds are described in U.S. Pat. No. 4,310,519. In addition, certain derivatives of these basic fermentation products have been prepared. Some of the avermectins contain a 22,23-double bond. This may be selectively reduced to prepare the ivermectin compounds discussed above. In addition, the avermectins possess a disaccharide moiety at the 13-position consisting of the a-L-oleandrosyl-a-L-oleandrosyl group. One or both of these saccharide groups may be removed as described in U.S. Pat. No. 4,206,205. The thus produced aglycone derivatives have a hydroxy group at the 13-position. This group may be removed to form the 13-deoxy compound as described in U.S. Pat. Nos. 4,171,314 and 4,173,571. On the avermectin compounds and derivatives are several hydroxy groups which may be acylated as described in U.S. Pat. No. 4,201,861.
A series of compounds identified as milbemycin compounds have the same 16 membered macrocyclic ring as do the avermectin compounds, although they do not have the disaccharide moiety and also differ in the nature of other substituent groups. These compounds are disclosed in U.S. Pat. No. 3,950,360 and they also would be expected to benefit in their spectrum of activity by the instant process and formulations.
Various medicaments, including avermectin compounds/milbemycin compounds, have traditionally been administered orally or by injection (subcutaneous, intramuscular) to animals, including humans. In the context of feedstock animals, i.e. meat-producing animals, such avermectin compounds/milbemycin compounds are sometimes added to the animals"" food. Such oral administration, however, does not effectively deliver the proper dosage to each and every animal. Significantly, animals that are sick often do not eat or drink properly. These sick animals, however, may be in greatest need such medicaments, including one or more avermectin compounds/milbemycin compounds.
Administration of avermectin compounds/milbemycin compounds to feedstock animals via intramuscular injection is an effective, but undesirable route of dosing. This route requires sterile procedures that can be difficult to maintain under field conditions. Intramuscular injections often result in tissue bruising, injection site lesions and concomitant product loss post-mortem.
Subcutaneous injection can be difficult to administer and can cause swelling at the injection site. Furthermore, subcutaneous injections may be given intramuscularly by mistake and reduce the effectiveness of the active compound. Animals/humans do not like injections and can move during the administration causing the needle to break off at the injection site. This creates a hazard for the animal/human and a contaminant in the food chain.
What is needed is a method to administer one or more parasiticides to animals, including humans, where that method is both cost-effective and time-effective.
Applicants"" invention includes a method to treat an animal in need thereof with one or more parasiticides by administering those one or more parasiticides to the nasal pharynx of the animal. Applicants"" invention further includes a method to increase blood levels of one or more avermectin compounds/milbemycin compounds such that the blood levels of those one or more avermectin compounds/milbemycin compounds reach a maximum concentration in about 24 hours, and such that those blood levels exceed about 2 ng/ml for at least 96 hours post administration.